Or use 3D BRL-CAD and when you are satisfied with the result, re-click it into qcad. These are my 3D models: http://ronja.twibright.com/3d/
BRL-CAD is 25 years of U. S. Army development so I hope it will be of use in your case too :)
Indeed, releasing it was one of the few good things my government has
done in the past few years. Its user interface is pure hell to learn,
Don't worry, it is compensated by the breaches of Geneve convention.
Hey, my government is above the law, haven't you heard?
-Dave